The phrase "jump the shark" was coined in the mid-1980s to refer to a moment at which a television show passed its peak and started declining in quality, if not in popularity. The phrase refers to an episode of Happy Days from September 20, 1977, in which super-cool hoodlum Arthur "Fonzie" Fonzarelli literally jumps over a shark while water skiing. This feat stands out in Happy Days lore because it was so far-fetched and so different from the show's original premise of family life in the 1950s. Jumping the shark usually involves some type of large change in a show. For example, Cast changes: If a main character leaves the show, producers have two options: write the character off the show or hire a new actor to play the same character. The show's success after such a change depends to a great degree on how important that character (or actor) was to the show. Some shows have been able to send main characters away (ER), kill them off (Star Trek: The Next Generation), or switch actors in the same role (Bewitched) without jumping the shark, but many shows die when they lose a main character. New characters: To put it bluntly, babies can kill a show. If a TV show isn't originally about family life, suddenly inserting a "family" element changes the show, most often to its detriment. Usually, a new "cute" child character is brought in when the original child character grows up and is no longer "cute." (Consider Raven-Symoné's appearance on The Cosby Show as a replacement for no-longer-cute-enough Keshia Knight Pulliam.) And it isn't always babies: it could be an angst-filled teenager (April on Gilmore Girls) or a full-grown adult (Nick on Family Ties). Setting changes: When your favorite characters suddenly head for new climes, that show may have jumped the shark. Consider the sitcom Laverne & Shirley. For five seasons, these comic roommates drank their milk and Pepsi in Milwaukee, Wisconsin. In the sixth season, under the pretense of having lost their jobs at the brewery to automation, they moved to Burbank, California. The show declined in quality and popularity and didn't last long after the move. Gimmicks: Sometimes, in an attempt to appear fresh and revive a show, writers and producers will resort to gimmicks. Signs to watch for: an episode in 3-D, an entire episode done as a musical, and a sudden influx of "special guest stars." Change in the premise: This is the worst way to jump a shark. If one of the show's ongoing points of conflict is resolved, what next? One common point of conflict on TV shows is sexual tension between two main characters; will they or won't they ever get together? If that conflict is suddenly resolved, most often by them getting together (like Ross and Rachel and Chandler and Monica on Friends), a major element of the show is gone. That's a sure sign that the show has jumped the shark and is on its decline.